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Groundwater is the water that fills the small spaces between rock particles (sand, gravel, etc.) or cracks in solid rock. Rain, melting snow, or surface water becomes groundwater by seeping into the ground and filling these spaces. The top of the water-saturated zone is called the “water table.” When water seeps in from the surface and reaches the water table, it begins moving towards points where it will either flow vertically to a deeper aquifer layer or it will flow horizontally to a place where it can escape, such as wells, rivers, or lakes.An aquifer is any type of geologic material, such as sand or sandstone, which can supply water to wells or springs. Some areas may have multiple aquifers at different depths, if the local geology contains several layers of sand or bedrock that can store and transmit water. Contrary to popular belief, an aquifer is usually not an “underground river.” A better analogy is that an aquifer is an underground sponge, with water stored in the pore spaces between grains of rock or sand. Wells work by extracting water from those pore spaces and pumping that water to the land surface.
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Most cities in the State of Minnesota obtain their drinking water from underground aquifers. The City of Winona owns and operates eight large capacity water supply wells. These wells draw water from groundwater aquifers located 400-110000 feet underground. Despite these depths, the groundwater aquifers that serve the Winona wells are vulnerable to contamination from human activities at the land surface. Because it is cheaper to prevent contamination than it is to treat contaminated water, Winona is looking for help from its residents to protect our water supply aquifers.
Wells can become polluted when substances that are harmful to human health get into the groundwater. Water from these wells can be dangerous to drink when the level of pollution rises above health standards. The City of Winona regularly samples the water from their wells and provides an annual Consumer Confidence Report to residents. The most recent report can be located on the City of Winona’s website.
There are many ways that groundwater can become contaminated. Here are some common examples of contamination sources:
The City of Winona is working with citizens to protect drinking water supplies by implementing our Wellhead Protection Plan. This plan has been prepared in conjunction with several local, county and state agencies. The Minnesota Department of Health is the lead agency for the State’s program and will assist communities with defining wellhead protection areas and developing plans to protect wells.
What Can You Do?
In order for the Wellhead Protection Plan to be successful, the citizens of Winona need to remain environmentally aware. There are several steps that you can take to help our planning efforts succeed:
The City of Winona has also identified private wells that fall within the wellhead protection area. A side benefit of the Wellhead Protection Plan is that it not only protects the municipal water supply wells, but it will also help protect private wells.
Private well owners are encouraged to obtain educational information about how to best manage their wells. The Minnesota Department of Health has a website that contains much useful information for well owners including a Well Owner’s Handbook.
If you are interested in having the water in your private well tested, more information can be found at the Winona County Soil and Water Conservation District’s website
If you currently have a well on your property that is not being used, you are required by law to seal that well or obtain a special permit to keep it open. If you need to seal your well, it must be done by a well contractor licensed in the State of Minnesota. There are numerous grant and cost-share opportunities to pay for well sealing costs. Contact Winona’s Public Works Department (507) 457-8269 for more information on possible upcoming well sealing grants.
Household hazardous wastes can be a source of contamination to local water bodies and groundwater when they are improperly handled or disposed of. The City of Winona encourages all residents to utilize Winona County’s Environmental Services for disposal of waste products.
Residential Turf Applications
Another potential source of contamination to local water bodies and groundwater supplies is from the over-application of fertilizers and other lawn/garden chemicals. Not only do these materials pollute local waterways, but excessive application is both unnecessary and costly to home owners. While it is unlikely that no single residential property is entirely responsible for contamination to local waters, the cumulative impacts of hundreds of properties applying excessive fertilizers can be detrimental to the local environment.
The University of Minnesota’s website contains useful information about lawn fertilization.
By following these guidelines, residential property owners can work together to ensure that our local waters are safe and clean for future generations to enjoy.